2 .TH MDADM 8 "" v2.0-devel-3
4 mdadm \- manage MD devices
10 .BI mdadm " [mode] <raiddevice> [options] <component-devices>"
13 RAID devices are virtual devices created from two or more
14 real block devices. This allows multiple devices (typically disk
15 drives or partitions there-of) to be combined into a single device to
16 hold (for example) a single filesystem.
17 Some RAID levels include redundancy and so can survive some degree of
20 Linux Software RAID devices are implemented through the md (Multiple
21 Devices) device driver.
23 Currently, Linux supports
37 .B MULTIPATH is not a Software RAID mechanism, but does involve
40 each device is a path to one common physical storage device.
42 .B FAULTY is also no true RAID, and it only involves one device. It
43 provides a layer over a true device that can be used to inject faults.
46 is a program that can be used to create, manage, and monitor
48 such it provides a similar set of functionality to the
51 The key differences between
58 is a single program and not a collection of programs.
61 can perform (almost) all of its functions without having a
62 configuration file and does not use one by default. Also
64 helps with management of the configuration
68 can provide information about your arrays (through Query, Detail, and Examine)
78 configuration file, at all. It has a different configuration file
79 with a different format and an different purpose.
82 mdadm has 7 major modes of operation:
85 Assemble the parts of a previously created
86 array into an active array. Components can be explicitly given
87 or can be searched for.
89 checks that the components
90 do form a bona fide array, and can, on request, fiddle superblock
91 information so as to assemble a faulty array.
95 Build an array without per-device superblocks.
99 Create a new array with per-device superblocks.
101 '''in several step create-add-add-run or it can all happen with one command.
105 This is for doing things to specific components of an array such as
106 adding new spares and removing faulty devices.
110 This mode allows operations on independent devices such as examine MD
111 superblocks, erasing old superblocks and stopping active arrays.
114 .B "Follow or Monitor"
115 Monitor one or more md devices and act on any state changes. This is
116 only meaningful for raid1, 4, 5, 6 or multipath arrays as
117 only these have interesting state. raid0 or linear never have
118 missing, spare, or failed drives, so there is nothing to monitor.
122 Grow (or shrink) an array, or otherwise reshape it in some way.
123 Currently supported growth options including changing the active size
124 of componenet devices in RAID level 1/4/5/6 and changing the number of
125 active devices in RAID1.
129 Available options are:
132 .BR -A ", " --assemble
133 Assemble a pre-existing array.
137 Build a legacy array without superblocks.
145 Examine a device to see
146 (1) if it is an md device and (2) if it is a component of an md
148 Information about what is discovered is presented.
152 Print detail of one or more md devices.
155 .BR -E ", " --examine
156 Print content of md superblock on device(s).
159 .BR -F ", " --follow ", " --monitor
166 Change the size or shape of an active array.
169 .BR -X ", " --examine-bitmap
170 Report information about a bitmap file.
174 Display help message or, after above option, mode specific help
179 Display more detailed help about command line parsing and some commonly
183 .BR -V ", " --version
184 Print version information for mdadm.
187 .BR -v ", " --verbose
188 Be more verbose about what is happening. This can be used twice to be
190 This currently only affects
193 .BR "--examine --scan" .
197 Be less verbose. This is used with
205 gives an intermediate level of verbosity.
208 .BR -b ", " --bitmap=
209 Give the name of a bitmap file to use with this array. Can be used
210 with --create (file should not exist) or --assemble (file should
215 Set the Chunksize of the bitmap. Each bit corresponds to that many
216 Kilobytes of storage. Default is 4.
221 Be more forceful about certain operations. See the various modes of
222 the exact meaning of this option in different contexts.
225 .BR -c ", " --config=
226 Specify the config file. Default is
227 .BR /etc/mdadm.conf .
228 If the config file given is
230 then nothing will be read, but
232 will act as though the config file contained exactly
233 .B "DEVICE partitions"
236 to find a list of devices to scan.
239 is given for the config file, then
241 will act as though the config file were empty.
247 for missing information.
248 In general, this option gives
250 permission to get any missing information, like component devices,
251 array devices, array identities, and alert destination from the
253 .BR /etc/mdadm.conf .
254 One exception is MISC mode when using
260 says to get a list of array devices from
264 .B -e ", " --metadata=
265 Declare the style of superblock (raid metadata) to be used. The
266 default is 0.90 for --create, and to guess for other operations.
270 .IP "0, 0.90, default"
271 Use the original 0.90 format superblock. This format limits arrays to
272 28 componenet devices and limits component devices of levels 1 and
273 greater to 2 terabytes.
274 .IP "1, 1.0, 1.1, 1.2"
275 Use the new version-1 format superblock. This has few restrictions.
276 The different subversion store the superblock at different locations
277 on the device, either at the end (for 1.0), at the start (for 1.1) or
278 4K from the start (for 1.2).
281 .SH For create or build:
285 Specify chunk size of kibibytes. The default is 64.
289 Specify rounding factor for linear array (==chunk size)
293 Set raid level. When used with
295 options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4,
296 raid5, 5, raid6, 6, multipath, mp, fautly. Obviously some of these are synonymous.
300 only linear, raid0, 0, stripe are valid.
303 .BR -p ", " --parity=
304 Set raid5 parity algorithm. Options are:
309 la, ra, ls, rs. The default is left-symmetric.
311 This option is also used to set the failure mode for
329 Each mode can be followed by a number which is used as a period
330 between fault generation. Without a number, the fault is generated
331 once on the first relevant request. With a number, the fault will be
332 generated after that many request, and will continue to be generated
333 every time the period elapses.
335 Multiple failure modes can be current simultaneously by using the
336 "--grow" option to set subsequent failure modes.
338 "clear" or "none" will remove any pending or periodic failure modes,
339 and "flush" will clear any persistant faults.
341 To set the parity with "--grow", the level of the array ("faulty")
342 must be specified before the fault mode is specified.
349 .BR -b ", " --bitmap=
350 Specify a file to store a write-intent bitmap in. The file should not
351 exist unless --force is also given. The same file should be provided
352 when assembling the array.
356 Specifty the chunksize for the bitmap.
359 .BR -n ", " --raid-devices=
360 Specify the number of active devices in the array. This, plus the
361 number of spare devices (see below) must equal the number of
363 (including "\fBmissing\fP" devices)
364 that are listed on the command line for
366 Setting a value of 1 is probably
367 a mistake and so requires that
369 be specified first. A value of 1 will then be allowed for linear,
370 multipath, raid0 and raid1. It is never allowed for raid4 or raid5.
372 This number can only be changed using
374 for RAID1 arrays, and only on kernels which provide necessary support.
377 .BR -x ", " --spare-devices=
378 Specify the number of spare (eXtra) devices in the initial array.
379 Spares can also be added
380 and removed later. The number of component devices listed
381 on the command line must equal the number of raid devices plus the
382 number of spare devices.
387 Amount (in Kibibytes) of space to use from each drive in RAID1/4/5/6.
388 This must be a multiple of the chunk size, and must leave about 128Kb
389 of space at the end of the drive for the RAID superblock.
390 If this is not specified
391 (as it normally is not) the smallest drive (or partition) sets the
392 size, though if there is a variance among the drives of greater than 1%, a warning is
395 This value can be set with
397 for RAID level 1/4/5/6. If the array was created with a size smaller
398 than the currently active drives, the extra space can be accessed
401 The size can be given as
403 which means to choose the largest size that fits all on all current drives.
409 that the array pre-existed and is known to be clean. This is only
410 really useful for Building RAID1 array. Only use this if you really
411 know what you are doing. This is currently only supported for --build.
417 run the array, even if some of the components
418 appear to be active in another array or filesystem. Normally
420 will ask for confirmation before including such components in an
421 array. This option causes that question to be suppressed.
427 accept the geometry and layout specified without question. Normally
429 will not allow creation of an array with only one device, and will try
430 to create a raid5 array with one missing drive (as this makes the
431 initial resync work faster). With
434 will not try to be so clever.
437 .BR -a ", " "--auto{=no,yes,md,mdp,part,p}{NN}"
438 Instruct mdadm to create the device file if needed, possibly allocating
439 an unused minor number. "md" causes a non-partitionable array
440 to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and
441 later) to be used. "yes" requires the named md device to have a
442 'standard' format, and the type and minor number will be determined
443 from this. See DEVICE NAMES below.
445 The argumentment can also come immediately after
450 is also given, then any
452 entries in the config file will over-ride the
454 instruction given on the command line.
456 For partitionable arrays,
458 will create the device file for the whole array and for the first 4
459 partitions. A different number of partitions can be specified at the
460 end of this option (e.g.
462 If the device name ends with a digit, the partition names add a'p',
463 and a number, e.g. "/dev/home1p3". If there is no
464 trailing digit, then the partition names just have a number added,
465 e.g. "/dev/scratch3".
467 If the md device name is in a 'standard' format as described in DEVICE
468 NAMES, then it will be created, if necessary, with the appropriate
469 number based on that name. If the device name is not in one of these
470 formats, then a unused minor number will be allocted. The minor
471 number will be considered unused if there is no active array for that
472 number, and there is no entry in /dev for that number and with a
479 uuid of array to assemble. Devices which don't have this uuid are
483 .BR -m ", " --super-minor=
484 Minor number of device that array was created for. Devices which
485 don't have this minor number are excluded. If you create an array as
486 /dev/md1, then all superblocks will contain the minor number 1, even if
487 the array is later assembled as /dev/md2.
489 Giving the literal word "dev" for
493 to use the minor number of the md device that is being assembled.
497 will look for super blocks with a minor number of 0.
501 Assemble the array even if some superblocks appear out-of-date
505 Attempt to start the array even if fewer drives were given than are
506 needed for a full array. Normally if not all drives are found and
508 is not used, then the array will be assembled but not started.
511 an attempt will be made to start it anyway.
514 .BR -a ", " "--auto{=no,yes,md,mdp,part}"
515 See this option under Create and Build options.
518 .BR -b ", " --bitmap=
519 Specify the bitmap file that was given when the array was created.
522 .BR -U ", " --update=
523 Update the superblock on each device while assembling the array. The
524 argument given to this flag can be one of
533 option will adjust the superblock of an array what was created on a Sparc
534 machine running a patched 2.2 Linux kernel. This kernel got the
535 alignment of part of the superblock wrong. You can use the
536 .B "--examine --sparc2.2"
539 to see what effect this would have.
543 option will update the
545 field on each superblock to match the minor number of the array being
546 assembled. This is not needed on 2.6 and later kernels as they make
547 this adjustment automatically.
551 option will cause the array to be marked
553 meaning that any redundancy in the array (e.g. parity for raid5,
554 copies for raid1) may be incorrect. This will cause the raid system
555 to perform a "resync" pass to make sure that all redundant information
560 option will correct the summaries in the superblock. That is the
561 counts of total, working, active, failed, and spare devices.
568 hotadd listed devices.
572 remove listed devices. They must not be active. i.e. they should
573 be failed or spare devices.
577 mark listed devices as faulty.
583 .SH For Examine mode:
587 In an array was created on a 2.2 Linux kernel patched with RAID
588 support, the superblock will have been created incorrectly, or at
589 least incompatibly with 2.4 and later kernels. Using the
593 will fix the superblock before displaying it. If this appears to do
594 the right thing, then the array can be successfully assembled using
595 .BR "--assemble --update=sparc2.2" .
601 start a partially built array.
605 deactivate array, releasing all resources.
608 .BR -o ", " --readonly
609 mark array as readonly.
612 .BR -w ", " --readwrite
613 mark array as readwrite.
617 If the device contains a valid md superblock, the block is
618 over-written with zeros. With
620 the block where the superblock would be is over-written even if it
621 doesn't appear to be valid.
629 is set to reflect the status of the device.
631 .SH For Monitor mode:
634 Give a mail address to send alerts to.
637 .BR -p ", " --program ", " --alert
638 Give a program to be run whenever an event is detected.
642 Give a delay in seconds.
644 polls the md arrays and then waits this many seconds before polling
645 again. The default is 60 seconds.
648 .BR -f ", " --daemonise
651 to run as a background daemon if it decides to monitor anything. This
652 causes it to fork and run in the child, and to disconnect form the
653 terminal. The process id of the child is written to stdout.
656 which will only continue monitoring if a mail address or alert program
657 is found in the config file.
660 .BR -i ", " --pid-file
663 is running in daemon mode, write the pid of the daemon process to
664 the specified file, instead of printing it on standard output.
667 .BR -1 ", " --oneshot
668 Check arrays only once. This will generate
670 events and more significantly
674 .B " mdadm --monitor --scan -1"
676 from a cron script will ensure regular notification of any degraded arrays.
682 alert for every array found at startup. This alert gets mailed and
683 passed to the alert program. This can be used for testing that alert
684 message to get through successfully.
691 .I md-device options-and-component-devices...
694 .B mdadm --assemble --scan
695 .I md-devices-and-options...
698 .B mdadm --assemble --scan
702 This usage assembles one or more raid arrays from pre-existing components.
703 For each array, mdadm needs to know the md device, the identity of the
704 array, and a number of component-devices. These can be found in a number of ways.
706 In the first usage example (without the
708 the first device given is the md device.
709 In the second usage example, all devices listed are treated as md
710 devices and assembly is attempted.
711 In the third (where no devices are listed) all md devices that are
712 listed in the configuration file are assembled.
714 If precisely one device is listed, but
720 was given and identify information is extracted from the configuration file.
722 The identity can be given with the
726 option, can be found in the config file, or will be taken from the
727 super block on the first component-device listed on the command line.
729 Devices can be given on the
731 command line or in the config file. Only devices which have an md
732 superblock which contains the right identity will be considered for
735 The config file is only used if explicitly named with
737 or requested with (a possibly implicit)
745 is not given, then the config file will only be used to find the
746 identity of md arrays.
748 Normally the array will be started after it is assembled. However if
750 is not given and insufficient drives were listed to start a complete
751 (non-degraded) array, then the array is not started (to guard against
752 usage errors). To insist that the array be started in this case (as
753 may work for RAID1, 4, 5 or 6), give the
759 option is given, either on the command line (--auto) or in the
760 configuration file (e.g. auto=part), then
762 will create the md device if necessary or will re-create it if it
763 doesn't look usable as it is.
765 This can be useful for handling partitioned devices (which don't have
766 a stable device number - it can change after a reboot) and when using
767 "udev" to manage your
769 tree (udev cannot handle md devices because of the unusual device
770 initialisation conventions).
772 If the option to "auto" is "mdp" or "part" or (on the command line
773 only) "p", then mdadm will create a partitionable array, using the
774 first free one that is not inuse, and does not already have an entry
775 in /dev (apart from numeric /dev/md* entries).
777 If the option to "auto" is "yes" or "md" or (on the command line)
778 nothing, then mdadm will create a traditional, non-partitionable md
781 It is expected that the "auto" functionality will be used to create
782 device entries with meaningful names such as "/dev/md/home" or
783 "/dev/md/root", rather than names based on the numerical array number.
785 When using this option to create a partitionable array, the device
786 files for the first 4 partitions are also created. If a different
787 number is required it can be simply appended to the auto option.
788 e.g. "auto=part8". Partition names are created by appending a digit
789 string to the device name, with an intervening "_p" if the device name
794 option is also available in Build and Create modes. As those modes do
795 not use a config file, the "auto=" config option does not apply to
806 .BI --raid-devices= Z
810 This usage is similar to
812 The difference is that it creates a legacy array without a superblock. With
813 these arrays there is no difference between initially creating the array and
814 subsequently assembling the array, except that hopefully there is useful
815 data there in the second case.
817 The level may only be 0, raid0, or linear. All devices must be listed
818 and the array will be started once complete.
829 .BI --raid-devices= Z
833 This usage will initialise a new md array, associate some devices with
834 it, and activate the array.
838 option is given (as described in more detail in the section on
839 Assemble mode), then the md device will be created with a suitable
840 device number if necessary.
842 As devices are added, they are checked to see if they contain raid
843 superblocks or filesystems. They are also checked to see if the variance in
844 device size exceeds 1%.
846 If any discrepancy is found, the array will not automatically be run, though
849 can override this caution.
851 To create a "degraded" array in which some devices are missing, simply
852 give the word "\fBmissing\fP"
853 in place of a device name. This will cause
855 to leave the corresponding slot in the array empty.
856 For a RAID4 or RAID5 array at most one slot can be
857 "\fBmissing\fP"; for a RAID6 array at most two slots.
858 For a RAID1 array, only one real device needs to be given. All of the
862 When creating a RAID5 array,
864 will automatically create a degraded array with an extra spare drive.
865 This is because building the spare into a degraded array is in general faster than resyncing
866 the parity on a non-degraded, but not clean, array. This feature can
867 be over-ridden with the
873 '''option is given, it is not necessary to list any component-devices in this command.
874 '''They can be added later, before a
878 '''is given, the apparent size of the smallest drive given is used.
880 The General Management options that are valid with --create are:
883 insist on running the array even if some devices look like they might
888 start the array readonly - not supported yet.
895 .I options... devices...
898 This usage will allow individual devices in an array to be failed,
899 removed or added. It is possible to perform multiple operations with
900 on command. For example:
902 .B " mdadm /dev/md0 -f /dev/hda1 -r /dev/hda1 -a /dev/hda1"
908 and will then remove it from the array and finally add it back
909 in as a spare. However only one md array can be affected by a single
920 MISC mode includes a number of distinct operations that
921 operate on distinct devices. The operations are:
924 The device is examined to see if it is
925 (1) an active md array, or
926 (2) a component of an md array.
927 The information discovered is reported.
931 The device should be an active md device.
933 will display a detailed description of the array.
937 will cause the output to be less detailed and the format to be
938 suitable for inclusion in
939 .BR /etc/mdadm.conf .
942 will normally be 0 unless
944 failed to get useful information about the device(s). However if the
946 option is given, then the exit status will be:
950 The array is functioning normally.
953 The array has at least one failed device.
956 The array has multiple failed devices and hence is unusable (raid4 or
960 There was an error while trying to get information about the device.
965 The device should be a component of an md array.
967 will read the md superblock of the device and display the contents.
972 then multiple devices that are components of the one array
973 are grouped together and reported in a single entry suitable
975 .BR /etc/mdadm.conf .
979 without listing any devices will cause all devices listed in the
980 config file to be examined.
984 The devices should be active md arrays which will be deactivated, as
985 long as they are not currently in use.
989 This will fully activate a partially assembled md array.
993 This will mark an active array as read-only, providing that it is
994 not currently being used.
1000 array back to being read/write.
1004 For all operations except
1007 will cause the operation to be applied to all arrays listed in
1012 causes all devices listed in the config file to be examined.
1020 .I options... devices...
1025 to periodically poll a number of md arrays and to report on any events
1028 will never exit once it decides that there are arrays to be checked,
1029 so it should normally be run in the background.
1031 As well as reporting events,
1033 may move a spare drive from one array to another if they are in the
1036 and if the destination array has a failed drive but not spares.
1038 If any devices are listed on the command line,
1040 will only monitor those devices. Otherwise all arrays listed in the
1041 configuration file will be monitored. Further, if
1043 is given, then any other md devices that appear in
1045 will also be monitored.
1047 The result of monitoring the arrays is the generation of events.
1048 These events are passed to a separate program (if specified) and may
1049 be mailed to a given E-mail address.
1051 When passing event to program, the program is run once for each event
1052 and is given 2 or 3 command-line arguements. The first is the
1053 name of the event (see below). The second is the name of the
1054 md device which is affected, and the third is the name of a related
1055 device if relevant, such as a component device that has failed.
1059 is given, then a program or an E-mail address must be specified on the
1060 command line or in the config file. If neither are available, then
1062 will not monitor anything.
1066 will continue monitoring as long as something was found to monitor. If
1067 no program or email is given, then each event is reported to
1070 The different events are:
1074 .B DeviceDisappeared
1075 An md array which previously was configured appears to no longer be
1080 was told to monitor an array which is RAID0 or Linear, then it will
1082 .B DeviceDisappeared
1083 with the extra information
1085 This is because RAID0 and Linear do not support the device-failed,
1086 hot-spare and resync operations which are monitored.
1090 An md array started reconstruction.
1096 is 20, 40, 60, or 80, this indicates that rebuild has passed that many
1097 percentage of the total.
1101 An md array that was rebuilding, isn't any more, either because it
1102 finished normally or was aborted.
1106 An active component device of an array has been marked as faulty.
1110 A spare component device which was being rebuilt to replace a faulty
1115 A spare component device which was being rebuilt to replace a faulty
1116 device as been successfully rebuild and has been made active.
1120 A new md array has been detected in the
1126 A newly noticed array appears to be degraded. This message is not
1129 notices a drive failure which causes degradation, but only when
1131 notices that an array is degraded when it first sees the array.
1135 A spare drive has been moved from one array in a
1137 to another to allow a failed drive to be replaced.
1143 has been told, via the config file, that an array should have a certain
1144 number of spare devices, and
1146 detects that it has fewer that this number when it first sees the
1147 array, it will report a
1153 An array was found at startup, and the
1164 cause Email to be sent. All events cause the program to be run.
1165 The program is run with two or three arguments, they being the event
1166 name, the array device and possibly a second device.
1168 Each event has an associated array device (e.g.
1170 and possibly a second device. For
1175 the second device is the relevant component device.
1178 the second device is the array that the spare was moved from.
1182 to move spares from one array to another, the different arrays need to
1183 be labelled with the same
1185 in the configuration file. The
1187 name can be any string. It is only necessary that different spare
1188 groups use different names.
1192 detects that an array which is in a spare group has fewer active
1193 devices than necessary for the complete array, and has no spare
1194 devices, it will look for another array in the same spare group that
1195 has a full complement of working drive and a spare. It will then
1196 attempt to remove the spare from the second drive and add it to the
1198 If the removal succeeds but the adding fails, then it is added back to
1202 The GROW mode is used for changing the size or shape of an active
1204 For this to work, the kernel must support the necessary change.
1205 Various types of growth may be added during 2.6 development, possibly
1206 including restructuring a raid5 array to have more active devices.
1208 Currently the only support available is to change the "size" attribute
1209 for arrays with redundancy, and the raid-disks attribute of RAID1
1212 Normally when an array is build the "size" it taken from the smallest
1213 of the drives. If all the small drives in an arrays are, one at a
1214 time, removed and replaced with larger drives, then you could have an
1215 array of large drives with only a small amount used. In this
1216 situation, changing the "size" with "GROW" mode will allow the extra
1217 space to start being used. If the size is increased in this way, a
1218 "resync" process will start to make sure the new parts of the array
1221 Note that when an array changes size, any filesystem that may be
1222 stored in the array will not automatically grow to use the space. The
1223 filesystem will need to be explicitly told to use the extra space.
1225 A RAID1 array can work with any number of devices from 1 upwards
1226 (though 1 is not very useful). There may be times which you want to
1227 increase or decrease the number of active devices. Note that this is
1228 different to hot-add or hot-remove which changes the number of
1231 When reducing the number of devices in a RAID1 array, the slots which
1232 are to be removed from the array must already be vacant. That is, the
1233 devices that which were in those slots must be failed and removed.
1235 When the number of devices is increased, any hot spares that are
1236 present may be activated immediately.
1240 .B " mdadm --query /dev/name-of-device"
1242 This will find out if a given device is a raid array, or is part of
1243 one, and will provide brief information about the device.
1245 .B " mdadm --assemble --scan"
1247 This will assemble and start all arrays listed in the standard confile
1248 file. This command will typically go in a system startup file.
1250 .B " mdadm --stop --scan"
1252 This will shut down all array that can be shut down (i.e. are not
1253 currently in use). This will typically go in a system shutdown script.
1255 .B " mdadm --follow --scan --delay=120"
1257 If (and only if) there is an Email address or program given in the
1258 standard config file, then
1259 monitor the status of all arrays listed in that file by
1260 polling them ever 2 minutes.
1262 .B " mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/hd[ac]1"
1264 Create /dev/md0 as a RAID1 array consisting of /dev/hda1 and /dev/hdc1.
1267 .B " echo 'DEVICE /dev/hd*[0-9] /dev/sd*[0-9]' > mdadm.conf"
1269 .B " mdadm --detail --scan >> mdadm.conf"
1271 This will create a prototype config file that describes currently
1272 active arrays that are known to be made from partitions of IDE or SCSI drives.
1273 This file should be reviewed before being used as it may
1274 contain unwanted detail.
1276 .B " echo 'DEVICE /dev/hd[a-z] /dev/sd*[a-z]' > mdadm.conf"
1278 .B " mdadm --examine --scan --config=mdadm.conf >> mdadm.conf"
1280 This will find what arrays could be assembled from existign IDE and
1281 SCSI whole drives (not partitions) and store the information is the
1282 format of a config file.
1283 This file is very likely to contain unwanted detail, particularly
1286 entries. It should be reviewed and edited before being used as an
1289 .B " mdadm --examine --brief --scan --config=partitions"
1291 .B " mdadm -Ebsc partitions"
1293 Create a list of devices by reading
1294 .BR /proc/partitions ,
1295 scan these for RAID superblocks, and printout a brief listing of all
1298 .B " mdadm -Ac partitions -m 0 /dev/md0"
1300 Scan all partitions and devices listed in
1301 .BR /proc/partitions
1304 out of all such devices with a RAID superblock with a minor number of 0.
1306 .B " mdadm --monitor --scan --daemonise > /var/run/mdadm"
1308 If config file contains a mail address or alert program, run mdadm in
1309 the background in monitor mode monitoring all md devices. Also write
1310 pid of mdadm daemon to
1311 .BR /var/run/mdadm .
1313 .B " mdadm --create --help"
1315 Providew help about the Create mode.
1317 .B " mdadm --config --help"
1319 Provide help about the format of the config file.
1323 Provide general help.
1334 lists all active md devices with information about them.
1336 uses this to find arrays when
1338 is given in Misc mode, and to monitor array reconstruction
1344 The config file lists which devices may be scanned to see if
1345 they contain MD super block, and gives identifying information
1346 (e.g. UUID) about known MD arrays. See
1352 While entries in the /dev directory can have any format you like,
1354 has an understanding of 'standard' formats which it uses to guide its
1355 behaviour when creating device files via the
1359 The standard names for non-partitioned arrays (the only sort of md
1360 array available in 2.4 and earlier) either of
1366 where NN is a number.
1367 The standard names for partitionable arrays (as available from 2.6
1374 Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2".
1378 was previously known as
1382 For information on the various levels of
1386 .UR http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/
1387 http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/
1390 for new releases of the RAID driver check out:
1393 .UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches
1394 ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches
1399 .UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/
1400 http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/
projects / thirdparty / mdadm.git / blob